It's worse than that. Mowing that old dead brush is going to break it turning a portion of it into powder in the back and the rest kindling. From having worked in a lumber mill I can tell you the bag could literally explode.

By removing all the dead grass, it leaves more room and nutrients for the new grass to grow. Prairies are meant to burn every now and then and the plants have deep roots that let them recover from the fire.

Let's say you're on your way to school/work/whatever. You could go straight there easily, or you could take a detour through the ghettos of Detroit before heading to your destination. Sure it works, but is it stupid? I think yes.

I meant the "An Hero" as kind of an ironic title. Ss stated in the comments, he was driving a lawn mower that was likely powered by gasoline, which would easily have exploded - so he would have in effect committed suicide. An hero.